The type of rock formed from the cementing of small pieces of older rocks, shells, soils, and dead plants and animals is sedimentary rock.

Here's why:

* Sedimentary rocks are formed by the accumulation and cementation of sediments. These sediments can be derived from various sources, including:

* Weathering and erosion of existing rocks (igneous, metamorphic, or even other sedimentary rocks)

* Organic material like shells, bones, plant matter, and even fossilized remains.

* Chemical precipitation from water solutions.

Let me know if you'd like to learn more about sedimentary rocks!